Details' contents matches a new details-content pseudo element.
Further work is required to make this pseudo-element behave per spec.
This pseudo should be element-backed per
https://drafts.csswg.org/css-pseudo/#element-backed
After we absolutize the contents of :has(), we check that those child
selectors don't contain anything that :has() rejects.
This is a separate path than the checks inside the parser, which is
unfortunate.
Fixes a WPT ref test. :^)
It's possible for absolutizing a selector to return an invalid selector
(eg, it could cause `:has()` inside `:has()`) so we need to be able to
express that.
Attempt 2! Reverts 2a5dbedad4
This time, set up a different combinator when producing a relative
invalid selector rather than a standalone one. This fixes the crash.
Original description below for simplicity because it still applies.
---
Selectors like `:is(.valid, &!?!?!invalid)` need to keep the invalid
part around, even though it will never match, for a couple of reasons:
- Serialization needs to include them
- For nesting, we care if a `&` appeared anywhere in the selector, even
in an invalid part.
So this patch introduces an `Invalid` simple selector type, which simply
holds its original ComponentValues. We search through these looking for
`&`, and we dump them out directly when asked to serialize.
Selectors like `:is(.valid, &!?!?!invalid)` need to keep the invalid
part around, even though it will never match, for a couple of reasons:
- Serialization needs to include them
- For nesting, we care if a `&` appeared anywhere in the selector, even
in an invalid part.
So this patch introduces an `Invalid` simple selector type, which simply
holds its original ComponentValues. We search through these looking for
`&`, and we dump them out directly when asked to serialize.
Instead of storing the three-part specificy for every selector,
just mash them together into a 32-bit value instead.
This saves both space and time, and matches the behavior of other
browser engines.
